A clock generating technology according to spread spectrum (SS) is known as a technology of reducing EMI (electro magnetic interference) noise caused by a clock in a transmitting/receiving system that transmits clock and data from a transmitting device to a receiving device. According to the SS technology, by temporally modulating the frequency of the clock transmitted from the transmitting device to the receiving device, a bandwidth of a frequency spectrum of the clock is extended and the peak intensity of the frequency spectrum is reduced, thereby reducing the EMI noise.
The transmitting device employing such SS technology needs to include a spread spectrum clock generator (SSCG) that generates a clock, the frequency of which is temporally modulated. Patent literatures 1 to 11 disclose inventions related to the SS technology and the SSCG.